Avril devolved after 2004 and by the time the TBDT era was over, she lost like 80% of her original fan base. You're supposed to mature musically as you grow older but she completely backtracked. Taylor does a good job of keeping things fresh without coming across as super dated even though she should probably start stepping it up as well, the "I hate boys" diary songs need to go at this point. It was cute when she was a teenager but now it's kind of much. I'm sure Taylor's smart enough to be aware of this and will probably release something of quality next time around, or at least I'm hoping.
Avril also isn't exactly the most intelligent artist business-wise, she was known for arguing with her labels over single choices that she wanted even though they clearly weren't the best picks, and consequently, they flopped. Avril tried to appeal to a new generation of children when she should've grew up with her original fan base.
Taylor, as calculated as she is, is very smart. Just watch her in any interview, sometimes she sounds like a flat-out business woman instead of a popstar
